


The Limit Does Not Exist

by kim_jignog



Category: EXO (Band)
Genre: Age Difference, Age Swap, Alternate Universe - College/University, Facials, Fluff, Glasses, M/M, Smut, Teacher-Student Relationship
Language: English
Status: Completed
Published: 2016-03-18
Updated: 2016-03-18
Packaged: 2018-05-27 10:04:49
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 11,377
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6280216
Author URL: https://archiveofourown.org/users/kim_jignog/pseuds/kim_jignog
Summary: <blockquote class="userstuff">
              <p>In which Kyungsoo's calculus professor wears his glasses instead of contacts for a day, and Kyungsoo kind of loses his mind.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> Inspired by the Unfair performances featuring Kim Kai looking hella fine in his glasses.

“Let’s look at the last example; this one is pretty straightforward. The question’s telling us to ‘Evaluate the integral from -2 to 1 of 2xdx using the limit definition.’ Now, recalling that the integral is really just the area under the curve…”

Kyungsoo isn’t listening. The people sitting to his left and right are diligently copying the Riemann sums Jongin is writing on the board into their notes, but Kyungsoo is far too distracted by the way the professor’s slacks hug his ass when he turns around to concern himself about the test he’ll be taking on this material the week after next. Jongin’s broad shoulders flex as he reaches up to sketch a crude graph to the left of the integral he’s written, and Kyungsoo’s tongue darts out to wet his full lips. Baekhyun’s foot knocks into the side of his desk.

_“If you start drooling I swear to god I’m dropping this class, asshole.”_

Kyungsoo glares at his best friend out of the corner of his eye, but Jongin is facing the class again and the student’s eyes automatically focus on the elegant, black-rimmed glasses that sit on the bridge of Jongin’s nose. Kyungsoo had never known before today that the professor’s eyesight was anything less than perfect, but Jongin had explained to a curious student in the front row that due to inflammation, his optometrist has advised him not to wear his contact lenses for the next week or two. He looks much older than he is with the spectacles, and Kyungsoo feels much hotter under the collar than he usually does during this class.

“Once we have all this information, we’re just going to plug it all into the limit. So the limit as x goes to infinity of the sum of f(ci)Δxi…”

Jongin looks sinful in those glasses, Kyungsoo muses, focusing on the way Jongin’s lips move as he speaks and idly imagining the way they might look doing other things. The professor’s eyes scan the room as he explains the properties of summations, locking on Kyungsoo’s for a moment longer than the others. Kyungsoo’s cock stirs in his tight jeans below the desk, and he offers the elder a small smirk in return. Jongdae snickers in the seat behind Kyungsoo. Jongin quickly turns back to the board.

In Jongin’s defense, Kyungsoo is difficult not to look at, his dark clothes, smoky eyeliner, and up-styled hair setting him apart from the rest of the students in the class, but Kyungsoo’s two fellow vocal majors in the class love to tease Kyungsoo about his crush every chance they get.

“I strongly suggest you try the problems on page 278 of your text for extra practice on this,” Jongin tells them as his 90 minutes come to an end. The students slowly trickle out of the classroom and Jongin walks to his desk, fixing his bangs with his hand and unwittingly driving Kyungsoo further up the wall.

“When are you gonna fuck him already?” Jongdae whines, settling dramatically into Baekhyun’s lap beside the youngest member of their friend group as he packs up his belongings. “I feel like a third wheel whenever I’m in the same room with you two.”

“He’s not gonna let me fuck him, Chen. Just look at him, he probably goes to church like twice a week.”

Baekhyun peers around the boy on his lap and eyes the professor thoughtfully, observing the elder as he checks his phone. “I don’t think it’s impossible. He’s way out of Jongdae’s league but not out of yours; you’re pretty hot.”

“Hey!” Jongdae cries, turning to face him. “He is not out of my league, and I’m closer to his age than Kyungsoo is!”

“Okay okay,” Kyungsoo shushes him, noticing the way that Jongin is now looking at them and hauling Jongdae off the other singer’s lap. “You’re sexy as hell, Chen. Come on, we gotta go.”

“Wait, Kyungsoo?” Jongin calls as the trio is almost at the door. Baekhyun catches the way Kyungsoo’s eyebrow ticks with arousal upon hearing his name fall from the elder’s lips and grins wickedly.

“We’ll meet up with you later, Soo. Dinner with the gang tonight?”

Kyungsoo nods his affirmation and walks over to the desk where Jongin stands. Jongdae closes the door behind them, and the two are left alone in the classroom.

“Kyungsoo, how are you feeling about this material?” Jongin looks him in the eyes, and the way his glasses frame his face contributes greatly to the erection that is threatening to form in Kyungsoo’s black skinny jeans. He just looks so sophisticated as he leans against his desk with his arms folded, the fabric of his sweater pulling tight across his biceps.

“It’s fine, I guess.”

“I noticed you spacing out a lot in class today. Is everything alright?”

_No, it’s not. Your glasses make me want to bend you over your desk and fuck you so hard that your legs shake and you come all over my classmates’ ungraded quizzes._

“Yeah, everything’s fine. I’m just a little distracted lately, I’m sorry.”

“Is there anything I can do to help?”

Kyungsoo swallows.

“No, professor.”

“Kyungsoo…” Jongin leans closer, and his breath scents of cool spearmint. “I can tell there’s something going on with you. If you don’t want to talk to me about it that’s fine, but I don’t want to see your grades start slipping because you’re being eaten up by whatever this is. It’s not just today, you’ve been looking like something’s troubling you for weeks whenever you’re in this class.”

Jongin’s cologne is spicy and inviting, and the ceiling lights reflect off the lenses of his spectacles. Kyungsoo wants nothing more than to ravish and debauch the angel in front of him. His mind wanders off again and he forgets to answer, and traces of concern fill Jongin’s warm, dark eyes.

“Kyungsoo?”

“Hm? What?”

“Kyungsoo, are you alright?” Jongin touches the side of Kyungsoo’s face, and something inside of the younger snaps. Without thinking, he grabs a handful of Jongin’s sweater and yanks him down for a heated, passionate kiss.

The surprised sound Jongin makes is so cute, Kyungsoo thinks, and he wastes no time in tracing the elder’s lips with his tongue. Jongin automatically kisses back for two glorious seconds before tearing away as if he’s been burned, backing up until his back collides with the board.

“Kyungsoo, what the hell are you doing?”

“Are you straight?” Kyungsoo asks, following his professor’s footsteps until he has the elder pressed against the board. Jongin flusters, and that’s all the answer Kyungsoo needs. Their lips connect again, and this time, the taller man doesn’t shove him away.

Jongin is a great kisser, Kyungsoo notes. He doesn’t know why he’s surprised, since Jongin is at least ten years older than him, but he’s always pegged Jongin as the type of guy who’s more interested in math and his dogs than relationships. He’s hesitant, but Kyungsoo easily coaxes his mouth open with his tongue, pressing himself closer and resting a hand on the professor’s waist. Jongin tastes as good as he smells; in addition to the fresh spearmint, Kyungsoo also tastes traces of banana lip balm as he devours his lips. The elder’s tongue slowly becomes more daring, and Kyungsoo thinks he could fly when he feels it tracing his own soft, kiss-swollen lips.

When Kyungsoo’s hand drops down to grope the elder’s ass, he’s quickly shoved away again. Jongin is flushed and panting, and Kyungsoo has never wanted to fuck someone so badly in his life.

“No way Kyungsoo, you’re a student.”

“You’re hard,” Kyungsoo notes, and the professor’s hands fly to cover the growing tent in his pants.

“W-why are you doing this?”

“Your glasses…” Kyungsoo nearly growls, advancing again and pressing his knee between Jongin’s thighs, “…make me want to _ruin_ you.”

The elder is beginning to tremble with adrenaline, and it makes Kyungsoo’s cock absolutely ache with need.

“M-my glasses…?” Jongin’s hand comes up to touch the delicate rims he had forgotten were on his face. Kyungsoo’s eyes follow the movement hungrily. He starts to say something else but Kyungsoo is kissing him again, and this time when Kyungsoo’s hands grip his ass, he does nothing to stop them.

Jongin is fighting a war in his mind that he never imagined he would have to fight: whether he should let this affair with this (admittedly gorgeous) student go on, or if he should stop Kyungsoo in his tracks before he risks losing his job. It’s been months since he last had sex, and the tantalizing rub of the younger man’s erection against his leg has him quickly beginning to favor the first option. Kyungsoo releases his lips and moves down to kiss his neck instead, not hesitating to suck a dark hickey in a spot that would be impossible to conceal. Jongin’s resolve shatters.

“L-lock the door.”

Kyungsoo grins wickedly, quickly pulling away to lock the door to Jongin’s classroom. Something is telling Jongin that he’ll regret this, but the outline of his student’s cock in his jeans is enough to make him forget the aftermath.

Jongin submits easily to Kyungsoo’s ministrations once he allows himself to relax. The younger’s leather jacket falls to the floor, and Kyungsoo loves the look that fills Jongin’s eyes as he drinks in the sight of Kyungsoo’s tattoos for the first time. He briefly wonders if he’s the professor’s type, because Jongin’s breath seems to come a little quicker as he traces the dark, tribal designs that flow over Kyungsoo’s bicep.

“These are so gorgeous…”

Kyungsoo replies with a smirk and pulls Jongin’s sweater over his head, careful not to disturb his glasses as he does. “They’re not done yet,” he tells him, admiring the elder’s toned torso and using his finger to trace the outline of his abs. “Once they are, I plan on getting more in… other places.”

His breath tickles Jongin’s ear, and the elder shudders.

“I can’t wait to see them.”

The hidden promise of a next time makes Kyungsoo giddy. His fingers acquaint themselves with the outline of Jongin’s cock in his pants as they kiss, but he doesn’t draw down the zipper until Jongin voices his consent by way of a breathy, “please, Kyungsoo…”

Jongin is bigger than Kyungsoo expected, but the student is pleased to discover that he’s still bigger. He unhurriedly strokes the elder to full hardness, savoring the way the sole object of all his fantasies for the past three months falls apart under his touch.

“You look so pretty,” he tells him, and Jongin shivers a little at the velvety tone of Kyungsoo’s voice. It makes him feel powerful, and he presses Jongin more firmly into the whiteboard. The elder’s shirt rubs away the integrals written in black dry erase marker there. Neither of them care.

Kyungsoo sinks to his knees in front of his teacher, and Jongin looks freshly alarmed by the situation until thick lips wrap around the head of his cock, tasting, but not sucking. Jongin groans, the sound loud and lecherous in the quiet of the lecture hall as Kyungsoo mouths down the sides of his rigid length, fingers instinctually seeking purchase in the younger’s inky hair. It musses Kyungsoo’s hairstyle, but the student doesn't mind, allowing his eyes to close and running his own hands up the elder’s strong thighs as he licks a fat stripe up the underside.

Kyungsoo wouldn’t say that he sucks a lot of dick, but he’s proud to say that he certainly knows his way around one. The sound that comes from Jongin’s throat when he finally sinks his head down only encourages him further. He wants to be the best fuck Jongin has ever had, and with that goal in mind, he blows the elder loudly and messily, all while gazing up at him with hooded, kohl-rimmed eyes. It takes him four tries to fit the whole thing down his throat, but if Kyungsoo is being honest with himself, he probably could have done it in two. The way Jongin whines with pleasure when Kyungsoo’s throat flutters and contacts around his length is enough to make up for the discomfort of choking.

He doesn’t stop until Jongin stops him, slowly guiding his head off his slick cock with both hands. He’s flushed, panting, and just beginning to glimmer with sweat, and the only thing Kyungsoo can think about is how badly he wants to wreck the man standing in front of him. He rises to his feet, intent set on removing the rest of the elder’s clothing, but is more than surprised when he suddenly finds himself shoved up against Jongin’s heavy desk.

“W-what are you doing?”

“Returning the favor?” Jongin says as if it’s the most obvious thing in the world. Kyungsoo’s brain is having trouble making sense of words right now, but when Jongin sinks to his knees in front of him, he understands.

Oh god.

Oh _god_.

If Kyungsoo had imagined that Jongin would look good on his knees, he looked positively fantastic in real life. The lenses of his glasses catch again the ceiling lights as he looks up at Kyungsoo with a smirk, dragging the zipper of the younger’s jeans down with his teeth and nuzzling his face into the prominent bulge there.

“You did well,” he teases, and Kyungsoo still can’t believe he’s actually about to get head from Professor Kim Jongin. “But let me show you how a grown-up does it.”

Kyungsoo wishes more than anything else in his life that he had been able to take a picture of Jongin’s face as he finally frees his erection from his far-too-tight jeans, drinking in the sight for the first time. Shock and arousal paint his expression at the size, pupils dilating as his eyes automatically cross in order to focus on the hard length bobbing above his nose. Kyungsoo would laugh, but the sight is too erotic for him to do anything but gasp as Jongin plants wet kisses down the sides of his cock, stroking until the whole thing is slick with spit before moving back up to suck properly and okay, maybe Kyungsoo was wrong about Jongin not knowing what he’s doing after all.

His mouth is tighter and hotter than Kyungsoo ever imagined it would be in his months of fantasizing about his professor. Jongin’s style is different from Kyungsoo’s, however; every stroke of his tongue is calculated and finessed, while Kyungsoo is all about passion and creating enticing visuals for his partner. He quickly catches on to the best ways in which to make Kyungsoo moan, and Kyungsoo really wishes Jongin weren’t so good because he’s making him look like an inexperienced child with how fast he’s coming apart.

Jongin discovers that eye contact is the key within three minutes, and as soon as he does, his eyes don’t leave Kyungsoo’s again. He looks so good with his mouth full of dick, Kyungsoo thinks, that eventually he has to be the one to break the heated stare the elder gives him, dark eyes twinkling behind the delicate lenses of his spectacles. Jongin slowly pulls off Kyungsoo’s cock, the younger groaning at the hot drag of his throat as he does, only to teasingly lap at the head once again with a satisfied smirk playing on his swollen lips.

“I have lube, but no condoms.”

“I have condoms,” Kyungsoo informs him, head spinning with arousal as he watches Jongin trace a thick vein on the underside of his cock with the tip of his tongue. He fishes his wallet out of his back pocket as Jongin moves his attention to his balls, accidentally sending his phone clattering to the ground in his haste, and plucks a foil packet out of his billfold.

“Where’s the lube?”

Jongin hums in response, the vibrations sending shocks through Kyungsoo’s entire body. “Desk drawer. Hand sanitizer bottle.”

Kyungsoo reaches over to check, only to find that there are actually two hand sanitizer bottles in the drawer. The first one he sniffs smells jarringly of rubbing alcohol, but sure enough, the second one smells of sweet mango. He uncaps it to pour some on his fingers, but Jongin reaches up to snatch it away from him.

“No way. I don’t know if you know what you’re doing or not.”

Kyungsoo scoffs at what he perceives as an insult and starts to form a retort, but ultimately decides that it will be more satisfying to make Jongin eat his words by fucking him into mindlessness a little later on. Therefore, he allows Jongin to stand, watching as the elder lubes his own fingers up as he kicks off his shoes and steps out of his pants. He has legs for miles, and Kyungsoo quite literally can’t bring himself look away as Jongin props one knee up on his desk, giving Kyungsoo a perfect view of his ass.

“Like something you see?” the professor drawls, quirking an eyebrow at the younger over his shoulder as he skirts his fingers over his own entrance. The weight of Kyungsoo’s stare is more arousing than uncomfortable, and Jongin rather enjoys the attention.

The ease with which Jongin sinks his middle finger in demonstrates to Kyungsoo just how often Jongin must do this to himself, and the sudden mental image of Jongin spread out on his bed taking his own fingers up his ass makes Kyungsoo’s cock throb painfully. He doesn’t like how cocky Jongin is getting, however, and feels an overwhelming desire to reduce his speech to nothing but desperate cries of Kyungsoo’s name. He strokes himself firmly, drinking in the sight before him and smirking to himself with the knowledge of what is to come, despite the fact that Jongin can’t see his face.

“You have the tightest little ass I’ve ever seen,” he comments as Jongin adds a second finger, earning a soft whine from the elder at the obscene compliment. To reinforce his words, Kyungsoo steps forward and grabs a handful of Jongin’s ass, making sure to press his heavy erection temptingly against the elder’s strong thigh as he does. Jongin moans, sinking his fingers in to the last knuckle and giving Kyungsoo a smoldering look out the sides of his eyes. The nerdy, meek Jongin Kyungsoo is so familiar with seems to have been possessed by the sex incarnate he’s looking at now, and honestly, Kyungsoo can’t decide which version of Jongin he prefers.

Jongin whimpers as his ring finger finds its way inside, and Kyungsoo unabashedly watches the way the elder carefully scissors them inside himself. He’s tempted to taste, to see if Jongin’s lube tastes as fruity as it smells, but he tells himself that this will certainly not be his last opportunity to do so.

“You might want to use four,” Kyungsoo warns him as helpfully as he can without sounding like he’s bragging (although this is Jongin, so he might be bragging just a little bit). His cock is dripping with anticipation of being buried inside the elder, and when he strokes himself, he makes sure it’s within Jongin’s line of sight. The pull of Jongin’s teeth on his shimmering lower lip as he watches is more than tantalizing, and Kyungsoo doesn’t think he can draw this out much longer.

He tears the foil packet in his hand with his teeth, dropping the trash atop the papers on Jongin’s desk and easily rolling on the condom. Jongin removes his fingers slowly, eyeing Kyungsoo’s erection appreciatively as he does.

“Sit down,” he instructs, pulling out his desk chair. “I’ll ride you.”

Kyungsoo snorts.

“Not this time, baby.”

Before he can protest, Jongin is bent over his own desk with a surprising amount of strength from the younger, and even when he can protest, the blunt head of Kyungsoo’s cock pressing against his stretched hole makes him not want to. Kyungsoo is still fully clothed despite Jongin being clad in nothing but his glasses and the pink that tints his skin, and the rough fabric of the distressed denim clinging to Kyungsoo’s thighs rubs against the elder’s skin in the most satisfying way possible.

The first breach of Kyungsoo’s cockhead through the tight ring of muscle has Jongin gasping aloud, and fuck, it really has been too long. Kyungsoo, to his credit, senses his discomfort and swallows down his moan of pleasure in favor of pressing soothing kisses over the sharp planes of the elder’s back. The act is a little more intimate than it should have been, and Jongin knows this in the back of his mind, but instead of feeling uncomfortable, the kisses are rather welcome and only make him feel warm. His muscles relax slowly, adjusting to the intrusion, and before long, the searing pain gives way to a dull, familiar burn.

I’m fine now, Jongin tries to tell him, but the words come out garbled. Kyungsoo understands anyways, resting one delicate hand on Jongin’s shoulder as he experimentally rocks his hips forwards. The elder softly hums his approval, biting his lip and glancing back the younger over his shoulder as a sign to go ahead.

Kyungsoo doesn’t need any more than that.

Usually he would be a gentleman and start out slowly, but he’s too eager to prove to Jongin that he’s not the inexperienced child the elder seems to think he is. Therefore, he drapes himself over the professor’s toned back, slowly drawing out until only the tip of his cock remains inside before slamming back in with a force that makes the desk shake and Jongin moan aloud. The sound is more satisfying than Kyungsoo ever imagined it would be, and the overwhelming need to elicit it again washes over him. He holds Jongin against him, giving him little room to squirm away before picking up his speed, drinking in every little moan and whimper that falls from his lips.

“Oh my g-god, Kyungsoo…” Jongin gasps out as the younger tightens his grip on his shoulder, and a flush creeps up his cheeks as the small part of him that isn’t dick-drunk yet reminds him how wrong this entire situation is. He’s a student, he’s a student, echoes endlessly in the back of his mind, but the rest of his brain is too distracted by how full he feels with Kyungsoo’s cock inside him, stretching him better than he ever could have dreamed.

Not that he’s ever had guilt-ridden wet dreams about how the vocal major in the fourth row with the eyeliner and piercings might fuck him if given the opportunity. That would be entirely inappropriate.

His last shred of concern for morality or ethics dissipates when Kyungsoo’s low voice materializes in his ear, his breath hot against the sensitive skin, and Jongin shivers violently.

“You like it, baby?”

The pet name used in such a lewd manner crumbles the last of Jongin’s defenses and he moans unabashedly, arching his back and turning his head to look over his shoulder at the younger.

“Fuck yes, baby harder…”

Kyungsoo doesn’t hesitate to follow instructions, and even when Jongin’s eyes fall closed in ecstasy, he can still feel the student’s heavy, lust-ridden gaze on him. As banal as the phrase “fucked into the desk” may be, there’s really no other way to describe the way Kyungsoo’s hips work so powerfully that Jongin’s travel coffee mug topples to the floor with the rocking of the tabletop, the elder’s desperate moans steadily rising in pitch.

“You look so good on my cock,” Kyungsoo tells him, his voice deep and rough from arousal, yet still attempting to come off as teasingly blasé. “Professor Kim Jongin, the picture of propriety, all spread out and moaning for me…”

“Shut up and fuck me harder, you son of a-”

Jongin’s voice breaks off into a breathless wail when Kyungsoo lifts his thigh onto the desk and strikes something in his core that almost makes the leg supporting his weight give out. His arms fly back to grab at whatever part of Kyungsoo he can reach, cheek consequently connecting with a stack of graded quizzes sitting on his desk as he fists a quivering hand in Kyungsoo’s dark t-shirt.

“Shit shit shit, y-yes!”

“Yeah?” the younger echoes, finding himself wishing he had his camera once again as he watches Jongin convulse beneath him. The elder’s muscles flutter helplessly around his throbbing member, and it takes an unspeakable amount of will to keep himself under control enough to properly reduce Jongin to a puddle on the desk.

He maintains the angle with some difficulty, but if Jongin’s sobs of pleasure as he strokes himself in tandem with Kyungsoo’s thrusts are any indication, he’s succeeding. His glasses are askew from his face being pressed against the wood of the desk, and on impulse, Kyungsoo pulls out and swiftly flips Jongin onto his back, sending several manilla file folders full of assignments to the ground.

Jongin opens his mouth to complain about the abrupt loss of warmth inside him, but before he can get the words out he’s being filled to the brink again, and this time, he can see the voracious look in Kyungsoo’s eyes. His hips are pulled to the edge of the desk and Kyungsoo resumes his rapid pace, releasing his hips from his grip long enough to bring his hands up and straighten his spectacles.

“I wanna see,” is all he growls, and Jongin is more than ready to show him whatever he wants to see as the younger fucks him with abandon. He knows how he must look: a panting, sweaty mess on his own desk with his legs splayed wide for the student, gasping and whining and grinding down for more like a slut, the elegant glasses perched on the bridge of his nose on the verge of fogging up from the heat and pheromones that thicken the air. He just can’t bring himself to care with the way the incessant stimulation to his prostate is making him see stars.

“Oh fuck me, fuck me, give me that fucking cock,” he hears himself babbling, fingers scrambling for purchase on Kyungsoo’s shoulders. The younger lets out a deep moan of his own, finally pulling the shirt over his head and tossing it away as he works to commit the vision of the man beneath him to memory.

“I’ll give it to you baby, don’t you worry… I’ll give it to you so good you’ll never want anyone else,” he promises, and this time, Jongin absolutely believes him.

It’s hot, almost too hot, and the view of the sweat beginning to drip off of Kyungsoo’s face riles Jongin up even more. He wants to lick him, and before he knows it he’s doing just that, half-sitting up and half pulling Kyungsoo down to run his tongue in a scorching path up the younger’s neck before reclaiming his plush lips. Kyungsoo dominates the kiss and Jongin lets him, relishing the taste of Kyungsoo’s tongue moving against his own as his long legs tightly wrap around the student’s waist, urging him closer and preventing him from moving away. Kyungsoo doesn’t seem to mind, moaning wantonly into Jongin’s mouth and snapping his hips up harder.

The desk is creaking now with the strength of Kyungsoo’s thrusts, and Jongin can barely form a coherent thought, let alone words. His fist works furiously over his cock, and when Kyungsoo’s hand replaces his, he can’t do anything but fall onto his back and cry out in ecstasy. It’s getting to be too much; the tension in Jongin’s muscles is starting to wind too tight, and at the rate Kyungsoo is making him fall apart, he doesn’t think he’s going to last much longer.

“P-please make me c-come, Kyungsoo,” he manages to sob as he clings to the younger’s arms, vaguely registering the strained curse that falls from Kyungsoo’s lips at the words. “I wanna come, I wanna come on your cock…”

“Yeah? You gonna come for me?” Kyungsoo asks breathlessly, no longer attempting to act like he isn’t just as aroused and tightly wound as Jongin. Jongin whines and nods, torn between rolling his hips up into Kyungsoo’s hand or rolling them down onto his cock.

_“Then come.”_

The sound of the younger’s rich, velvet voice positively dripping with desire is what brings him over the edge, the noise that tears from his throat as he spills all he has into Kyungsoo’s right hand loud enough to warrant the student covering his mouth with the other. His orgasm rocks him so hard that for a minute, nothing exists except for him, Kyungsoo, and the white-hot pleasure that courses through his veins like adrenaline, making him gasp and writhe against his will as the younger fucks him all the way through his high.

The sensation of Jongin’s walls quivering and contracting around his girth brings Kyungsoo dangerously close to coming, but he didn’t do all this work to sleep with his professor only to finish by filling a condom. It takes all of his self-control, but he manages to stave off his orgasm long enough for Jongin to thoroughly enjoy his before pulling out and maneuvering Jongin onto the floor. The elder’s eyes are smoldering behind the glittering lenses of his glasses, watching with rapture as Kyungsoo sheds the condom and strokes himself in front of him with practiced flicks of his wrist.

“Fuck, you gonna come all over me?” Jongin asks with a coy smile, shifting himself on his knees to lean closer to Kyungsoo’s fist as it works over his slick cock. “Gonna dirty up these glasses you like so much?”

“Fuck yeah I am,” Kyungsoo groans, hooded eyes locked on Jongin’s as he finally hits his peak and finishes with a desperate moan of the elder’s name. Jongin grins wider than he has all day, closing his eyes and opening his mouth as Kyungsoo comes in thick ribbons across his face, painting his skin (and glasses) with sticky white.

This time when Kyungsoo looks down, he really can’t help but reach for his camera. His come drips obscenely from the rim of Jongin’s glasses and onto the floor as the elder leans up to slowly lick each of his fingers clean, eyes locked on Kyungsoo’s phone all the while. It’s filthy; it’s far too salacious for Kyungsoo to handle, but it’s everything he’s been dreaming of, and he’s certain that after acquiring these photographs, he’ll never have to watch porn again.

“Can I keep these?” he asks after a minute of catching his breath, his voice still not quite steady. “You have no idea how incredible you look.”

Jongin giggles, clearly pleased with himself. “Only if you never show a soul.”

He stands on shaky legs with Kyungsoo’s assistance, and the younger wonders if he looks as wrecked as Jongin does right now. Watching his professor feebly attempt to clean himself up using the tissues on his desk while leaning against it for support fills him with an odd sense of masculine pride, and deciding that now is the right time to start acting like a gentleman, takes it upon himself to collect the papers (and coffee cup, gratefully empty) that were accidentally sent to the floor in the throes of their passion. Jongin smiles gratefully, shyly biting his lip and eyeing Kyungsoo’s. The younger takes the hint, stepping forward and gently pressing his lips against Jongin’s.

This kiss is more tender than the ones they shared previously, and Kyungsoo is only mildly alarmed by the affection he feels swelling up in his chest as Jongin’s hands rest chastely on his shoulders. He’s not so naïve to think that the two of them could actually be together (at least until he graduates), but maybe, just maybe, they could do this again sometime.

There are countless things left unsaid as they pull away, dark eyes locked on one another as they stand in the now silent lecture hall. The second hand on the clock ticks away endlessly as they search each other’s flushed faces for answers. It’s Kyungsoo who finally breaks the heavy tension when he decides he can’t stand it anymore.

“Not bad for an old man.”

Jongin scoffs, half-heartedly shoving Kyungsoo away and removing his glasses in order to make a feeble attempt to clean them. “I’m 35, you asshole. How obnoxious can you be?”

The words hold no venom, and Kyungsoo grins, leaning forward to press his forehead against the professor’s before sarcastically quoting the phrase he’s written countless times on Jongin’s calculus homeworks.

“The limit does not exist.”


	2. Chapter 2

“Since fucking when do you get As in Calculus?” Jongdae cries as the TA places Kyungsoo’s graded quiz face-up on his desk. “You don’t even listen in Calculus!”

“I go to office hours,” Kyungsoo replies, sharp eyes scanning the sparse corrections Jongin has made in his work. The TA hands Jongdae his quiz face-down, and Kyungsoo hides his laughter at the look on Jongdae’s face much more successfully than Baekhyun.

“ _Office_ _hours_ ,” the eldest mocks, earning himself a ruthless elbow in the bicep.

“Yes, _office_ _hours_ , you dick. Quit implying shit.”

“Who, me?” Baekhyun gasps, eyes widening in mock offense. “I implied nothing; I can’t believe you would accuse your best friend of such a terrible thing.”

“Overall, I was impressed with your quiz grades,” Jongin’s voice carries across the spacious room, and the chatter dies down a little as the students redirect their attention to the man in front. “Some of you just aren’t putting in the practice hours needed to succeed. If you got below a 70% on this, I very strongly recommend you come to office hours this weekend so we can work on it, alright?”

Dull murmurs of consent rise from the deject group of students as Jongin walks around his desk to retrieve a new stack of papers. “That being said, we’re just going to jump right into our next unit. Sehun’s going to bring you your guided notes. I’ll give you a brief overview, but as always, fill them out at home before next class.”

He hands the papers to his TA with a smile, and Kyungsoo feels himself doing the same as he watches. Jongin is still wearing his glasses every day despite the fact that his conjunctivitis is long gone.

“Here’s my theory,” he hears Baekhyun stage-whispering to Jongdae beside him. Kyungsoo rolls his eyes and accepts his paper from Sehun with a polite thank you. “Our Kyungsoo is so whipped that he’s willing to put in extra hours of work to get his grade up in hopes of impressing his precious Professor Kim.”

“Ooh, interesting!” Jongdae whispers just as indiscreetly, both of their bodies angled to observe the youngest as he pointedly ignores them. “So you think that he hasn’t smashed yet, but is still hoping to smash?”

“Precisely!”

“I’ve also observed that he drools approximately 36% less in class these days. How do you explain this development, Doctor Byun?”

“Oh my god, shut _up_!” Kyungsoo hisses through his teeth. “I am not whipped, I just happen to think he’s attractive! Don’t act like we don’t all see the way you look at that ridiculously tall Chem TA, Baek!”

Jongdae cackles out loud, and Baekhyun immediately flusters. Satisfied, Kyungsoo neatly places the notes into a folder and replaces it in his laptop bag.

“I’m gonna hang back and ask him why I got this question wrong,” Kyungsoo tells them as class comes to an end. “What time is rehearsal again?”

“Four,” Baekhyun replies, nimble fingers fiddling with his hair as he attempts to hide his blush at the mention of his crush. “Lu might literally wring your neck if you’re late for final rehearsal, though.”

“I know, I know,” he waves the elder off, rising from his seat with his quiz in hand. Jongin looks up from his phone as he approaches, his handsome face breaking into a smile.

“Mr. Do. If you’re here to invite me to the concert tomorrow night, I already bought my ticket.”

“That takes care of one thing,” Kyungsoo says, returning the smile, and he thinks he can almost hear the smirk on Jongdae’s face several rows of desks behind him. “But I was still hoping you could explain number twelve to me if you had the time?”

He walks behind the desk and sets the paper down in front of Jongin, looking at it over the elder’s shoulder while still maintaining a respectable distance between them. The professor scans over the work, nodding to himself as he finds the error.

“Mmm. So it does tend to get a little weird when you’re playing with these types of problems. First of all, tell me; what’s the derivative of the natural log of anything again?”

“One divided by that anything,” Kyungsoo recites, watching Jongin’s fingers as he jots some numbers on his paper in red ink.

“So we know that much,” he continues, looking up at Kyungsoo’s face as he speaks. Baekhyun and Jongdae are among the last students to leave, and the classroom grows silent as the stragglers make their way out. “Now to find the anti-derivative we have to-”

As soon as the door clicks shut, Kyungsoo pulls Jongin’s chair out from under the desk and eagerly presses plush lips against the elder’s own. Jongin is obviously taken aback, gasping and dropping his pen as Kyungsoo comfortably settles himself on his thighs. “I missed you,” he mutters, warm breath fanning over the elder’s face before kissing him again.

Jongin can’t help but kiss back for a moment before paranoia takes over again, gently pushing Kyungsoo back by his shoulders. “Shit, Kyungsoo, the door’s unlocked.”

“So?” Kyungsoo teases, attaching his lips to the column of Jongin’s neck and nibbling at the bronze skin.

“So I _like_ my job,” Jongin grits his teeth, hissing as Kyungsoo sucks gently over his pulse point. “If we’re doing this we’re locking the damn door.”

“Or we could get out of here,” Kyungsoo counters, nuzzling his nose against Jongin’s rapidly beating pulse. “And I could fuck you properly.”

“Where the hell do we have to go, Kyungsoo?” he groans when the younger bites down, eyes anxiously darting towards the door. “Either lock the door or wait till tomorrow when we can get some privacy after your show.”

“You’re so dirty,” Kyungsoo teases, reluctantly picking himself up off of Jongin’s lap and sauntering over to the door. “Do you do this with all your students, Professor Kim?”

“Never even dreamed of it,” Jongin replies honestly. “Just you.”

The lock clicks into place, and Kyungsoo takes his jacket off as he walks back over to the desk. Jongin’s eyes darken noticeably as his gaze falls on the ink decorating his arms. He doesn’t realize that Kyungsoo knows exactly what sort of effect the tattoos have on him.

“I haven’t stopped thinking about you,” Kyungsoo tells him in a voice as smooth as velvet as he braces a hand on the desk and leans down. “It’s been so long since last time.”

“Isn’t there anybody your own age that you talk to?” Jongin asks, his voice coming out a little breathless. The younger’s heart-shaped lips pull into a smile.

“There’s no one as satisfying as you.”

Their lips connect again, and this time, Jongin can’t resist. He doesn’t put up a fight when Kyungsoo pulls him out of his chair and pins him against the desk, instead opting to eagerly wrap his arms around the smaller man’s neck. Kyungsoo’s tongue brazenly explores his mouth, memorizing his taste, and Jongin almost feels embarrassed for getting too excited too quickly until he feels the obvious bulge pressing against his clothed thigh.

“I really wanna blow you,” Kyungsoo admits against his lips, their foreheads still pressed together as Jongin tries to grind his hips against the younger’s. “But we’re seriously all under direct orders from Luhan not to suck any dick until after the show to save our throats.”

“That must be difficult for Baekhyun,” Jongin says before he can stop himself, and Kyungsoo immediately breaks into a fit of laughter.

“No, I never said that! You didn’t hear it!”

“It’s so true though!”

Jongin tries to pout, but the laughter in Kyungsoo’s eyes is contagious. They both giggle even as Jongin unbuckles the younger’s belt, but the student’s snickers catch in his throat when Jongin’s callused hand pulls his cock out of his skinny jeans.

“Did I do this?” the elder asks innocently, referring to Kyungsoo’s half-hardness, and the younger scowls up at him.

“Don’t play coy. You were teasing me in class today.”

Jongin giggles as he sinks to his knees. “You’re right; I was.”

He gives a long lick from the base of Kyungsoo’s cock up to the tip, locking his gaze on the younger’s as he does. Kyungsoo gives a low moan of encouragement in return, gently running his fingers through Jongin’s hair and intentionally mussing the style. The elder’s tongue only teases the head of Kyungsoo’s cock for a moment before his lips finally sink down on it, too eager to delay any longer. He’s become quite accustomed to having his mouth full of Kyungsoo, really, and it’s exceptionally easy for him to adopt the rough and rapid pace that he knows will drive the younger wild.

“Fuck, just like that,” Kyungsoo breathes, confirming that of which Jongin is already aware. Jongin moans around the girth and fights the instinct to close his eyes, determinedly locking his sultry gaze on the student’s as he sucks. Kyungsoo’s breath comes quickly, the look in Jongin’s usually warm, friendly eyes making his toes curl in his boots with desire, and he’s painfully cognizant of the way the professor’s hips are rocking almost imperceptibly against the air out of desperation for friction. It drives him crazy knowing that Jongin is already so aroused by the thrilling taboo of the situation despite having yet to be touched.

“ _Dirty_ _little_ _slut_ ,” he mutters under his breath, accidentally voicing his less-than-pure thoughts aloud, but not so low that Jongin doesn’t hear. Kyungsoo isn’t sure if he would label the sound Jongin makes a whimper or a moan, but it does nothing but make his dick impossibly harder as Jongin slowly sinks his lips down until his nose touches Kyungsoo’s pelvis.

“Look at you, so eager on your knees like this…” he says lowly, gauging Jongin’s reaction to the degradation with a smirk on his face. The man’s fingers start to tremble, tightly gripping Kyungsoo’s clothes thighs as he starts to bob his head again with a desperate moan, pleasurable heat prickling under his skin at the words. It doesn’t go unnoticed.

“Do you want my cock in you that badly, baby?”

Jongin finally pulls himself off of Kyungsoo’s cock and gasps for air, dropping his right hand from Kyungsoo’s thigh to palm himself through his slacks. “Fuck, yes Kyungsoo, _please_ …”

“Strip,” he orders, and Jongin’s fingers immediately go to work untying his tie. Kyungsoo settles comfortably in Jongin’s desk chair and strokes himself while he waits, enjoying the way Jongin practically falls over himself in his haste to remove his clothes.

“Come here,” he instructs when Jongin is naked, beckoning palm-up for the elder to sit on his lap, and Jongin crawls up onto Kyungsoo’s thighs with the grace of a gazelle. Their lips connect again in a messy, scalding imitation of a kiss while Kyungsoo retrieves Jongin’s lube from the desk drawer without needing to look.

“I can’t blow you,” he reiterates against Jongin’s swollen lips when they finally break away for a quick breath of air, “but I can eat you out.”

Jongin freezes, and Kyungsoo can feel the professor’s pulse thrumming faster under his flushed skin. It’s something they haven’t done before, yet, but if the throbbing of Jongin’s cock against his own stomach is any indication, he’s far from being opposed to the idea.

“Bend over for me,” he whispers against Jongin’s adam’s apple, giving the elder’s ass a light smack to prompt him. Jongin quickly stands to comply, resting his elbows on the polished wood of the desk before glancing over his shoulder at Kyungsoo. “Good boy,” Kyungsoo croons, admiring the dips and curves of Jongin’s body as he pulls his t-shirt over his head.

“What the hell has gotten into you,” Jongin wonders aloud, the heat of his breath against the desk causing his glasses to fog. Full lips leave a trail of kisses down his spine, goosebumps materializing in their wake, and Jongin gasps when slender fingers press into his flesh, exposing all of him for Kyungsoo to see.

“I don’t know what you’re talking about,” Kyungsoo replies against Jongin’s skin, and the elder’s toes curl in his socks. The student’s tongue drags slow, hot and dirty over Jongin’s entrance, and the sound that he makes in response doesn’t quite make it out of his throat before Kyungsoo’s tongue is sliding inside. Nobody’s done this to Jongin since college, but it’s exceedingly obvious that Kyungsoo’s had some practice in his own past four years of uni, because the way his mouth works Jongin open with ease is just barely short of expert.

The sensation is foreign, yet vaguely familiar; it’s overwhelmingly pleasant nonetheless, and Jongin whimpers aloud as he pushes his hips back for more. Kyungsoo indulges him, relishing the broken moan that vibrates high in the elder’s throat. He doesn’t hesitate in the slightest, his own soft moan muffled by Jongin’s harsh breathing as he works his tongue deeper and blindly lubes up his fingers at the same time. The first digit is remarkably easy to push past the tight ring of muscle, and Jongin shows no signs of discomfort whatsoever as Kyungsoo finally confirms that yes, Jongin’s lube of choice is indeed citrus flavored.

It suits him, Kyungsoo thinks with a small smirk, savoring the unique flavor of both Jongin and mango on his tongue. The elder trembles under his touch as Kyungsoo stretches him open with a second finger, followed by a third, and before long, that’s not enough either.

“I need your cock, Soo,” he manages to gasp out, drunk on the feeling of Kyungsoo’s lips sucking ever so gently on his rim. “Oh god, please fuck me, Kyungsoo…”

“Such good manners,” Kyungsoo teases, slowly drawing his fingers out and admiring the way Jongin’s hole clenches around air at the loss. “Flip over; let me see your pretty face.”

Jongin obeys, lifting himself up onto the desk and pulling the younger closer with his legs. They kiss ferociously, fueled by desperation and lust, Jongin’s hand automatically reaching down to stroke Kyungsoo as they do.

“This is so fucked up,” Jongin moans to no one in particular when Kyungsoo breaks away to leave a fresh hickey on the elder’s neck. “I’m so going to hell for this.”

“Oh, would you just shut up?” Kyungsoo rolls his eyes, pushing Jongin onto his back and pulling his hips to the edge of the desk. “This is wrong, I’m your student, I’m too young for you; we both know it already.”

Jongin looks like he wants to retort, but he’s distracted by how pretty Kyungsoo’s hands look as he rolls on his condom and lubes himself up. “Besides,” Kyungsoo says with a smirk, “Haven’t we done this enough times already that we’re going to hell whether we stop now or not?”

He enters the elder with little to no difficulty as if proving his point, and Jongin’s head falls back against the desk with a dull thud. He’s right, Jongin knows; he’s spent far too many hours on Kyungsoo’s cock to still be pretending to feel guilty about it.

It’s a familiar routine by now. Kyungsoo always initiates their affairs, but Jongin is often the one who provokes him with sultry glances, lingering touches, and subtle teasing throughout class. He’s fortunate that the only people in the class who pay him any mind are too dense to see what’s really going on between the professor and his student, especially on days like today when Kyungsoo is too impatient to wait and catch Jongin in his private office later on. They’re as close to dating as they can be without saying the words aloud, despite their thirteen-year age gap, which bothers Jongin more than it does Kyungsoo. “I’m twenty-two; I graduate in three months,” Kyungsoo always reminds him. “After that, no one can stop us.”

Kyungsoo has always had a taste for older men, anyways.

He gradually learns that, despite his pure appearance, Jongin does not enjoy being treated like a prince in bed (or desk, if you will). He prefers it on the rough side, and Kyungsoo is more than happy to oblige. “Fuck, you’re always so tight for me,” he hisses through his teeth, taking advantage of Jongin’s flexibility and spreading his thighs wider. He draws out slowly until only the tip remains inside before driving back in, watching the way his cock disappears inside the elder’s pliant body with a low moan.

Jongin keens, running a hand through his own disheveled hair and looking up at the ceiling with unfocused eyes. Kyungsoo always makes him feel so full, and it’s always enough to allay his guilty conscience.

“Shit, you’re so big,” Jongin gasps, partly because it’s the truth and partly because he knows vocalizing the thought will only feed into Kyungsoo’s confidence. “More, give me more…”

Kyungsoo doesn’t require any more encouragement than that. He grips Jongin’s thighs and picks up his pace, and before long, Jongin is a mewling mess as he lets himself get pummeled.

“You’re so noisy, baby,” Kyungsoo says breathlessly, watching with bright eyes as he strikes something in Jongin that makes his back arch sharply off the desk with a broken scream. “Someone’s gonna hear you; someone’s gonna hear what a good little cockslut you are for me…”

“God, your voice is so fucking hot,” Jongin whines, the younger’s velvet voice dripping over him like warm honey. The blush that dusts his cheeks moments later indicates that this is a sentiment he hadn’t meant to voice aloud, but Kyungsoo couldn’t have been more pleased by the confession.

“Yeah? You like it when I tell you how well you take my cock, _Professor_?” he asks, dropping his voice into the low register he uses to croon the smooth R &B songs he always selects for his solos. “You like it when I tell you how pretty you look all spread out like this for me?”

“Oh fuck yes,” Jongin sobs, convulsing beneath him from pure pleasure. “Yes, god, give it to me, tell me…”

“ _Fucking_ _whore_ ,” Kyungsoo spits, his minor in acting making it easy to mask his fascination at the way Jongin’s body reacts so positively to the degradation behind a semblance of indifference. He files the new information away in a section of his mind dedicated solely to the professor, along with a note to himself to tease him for it later on.

He makes an active effort to piston his hips a little harder, to fuck Jongin so deep that he really does have to cover his own mouth to muffle his moans, and as usual, he’s successful. He doesn’t slow down even when Jongin looks absolutely wrecked, tears of pure rapture flowing from the sides of his eyes from the incessant stimulation and toned chest heaving with the effort of filling his lungs with air.

“Do you think you can come without me touching you?” Kyungsoo asks lowly, a smirk on his lips as he watches Jongin’s eyes widen in panic.

“No, no, no, please… please touch me Kyungsoo, I can’t…”

“I think you can,” sings Kyungsoo, heart-shaped lips curling into a wicked grin when a well-aimed thrust elicits a wail from the elder. Jongin quickly slaps a hand over his mouth, but Kyungsoo can still hear the high staccato of his whimpers with each of his thrusts.

“Such a needy little slut,” he muses, drinking in the view of the refined and elegant Kim Jongin looking so debauched. He doesn’t derive any pleasure from the act of calling Jongin names, he doesn’t think, but he certainly derives plenty from the way the professor sobs his name and clenches his muscles upon hearing them. “You’re gonna come just from being so full of my cock, aren’t you?”

“No,” Jongin sobs desperately, but Kyungsoo recognizes his tells by now, and knows how close to the edge he is. He ups his game, assuming a tight grip on Jongin’s thighs knowing that the elder will instinctually try to close them when he comes, and speeds up as much as he still can without sacrificing the depth of his thrusts. Jongin tries desperately to muffle his voice, but his scream of ecstasy is still sinfully loud as he comes untouched all over his stomach, splattering the golden skin with drops of ivory.

Kyungsoo pulls out moments later, quickly discarding his condom and stroking himself over Jongin’s body with urgent flicks of his wrist. Jongin is too fucked out to do anything but watch passively, run his fingers through the sticky mess settling into the gentle indentations of his abs, and lock his sated gaze on Kyungsoo’s rapacious one as he suggestively licks it off. Kyungsoo comes with Jongin’s name on his lips, all pretense of dominance forgotten as he trembles under the weight of Jongin’s lustful stare, shooting long ribbons of come over the elder’s lithe form. Jongin looks exceedingly satisfied, smiling brightly as he catches his breath and watches Kyungsoo unravel. The classroom is silent once again in the aftermath of the act, and Kyungsoo can’t help but return Jongin’s smile with a grin of his own.

“You made a mess again, didn’t you?” Jongin asks when he finally regains control of his voice, and Kyungsoo nods sheepishly.

“Sorry. Stay there, I’ll clean it up.”

Jongin doesn’t have much of a choice; he can’t quite feel his legs yet, but he’s still grateful for the extra time to collect himself while Kyungsoo gathers the papers that have been cast to the floor. “A mess here too,” Jongin muses to himself as he does, idly mixing Kyungsoo’s release with his own on his stomach and sucking on his fingers.

“Don’t,” Kyungsoo warns, and Jongin doesn’t have to turn his head to know how the younger is looking at him. “I don’t have the time or energy to get hard again, hyung.”

Jongin ignores him, scooping more of their combined semen onto his fingers before closing his lips around them with an exaggerated hum. He’s not surprised when he feels Kyungsoo’s tongue laving over his abs a moment later, cleaning up the remainder of the mess before leaning up for a kiss. The younger doesn’t hesitate to slide his tongue against Jongin’s, both of them moaning softly at the filthy slide of come between them, and Kyungsoo hisses softly when he feels Jongin’s throat flex as he swallows.

“You’re such a tease,” he grumbles, softly kissing the elder one more time before pulling away. “If I wasn’t trying to not get strangled by Luhan for being late, I’d wreck you.”

“I know,” Jongin smiles, gratefully accepting the hand Kyungsoo offers him. It takes them a little while to get the classroom clean and in order, especially when it comes to dissipating the heady scent of sex, but even after they get their clothes back on, Jongin’s hair is still a disaster, and Kyungsoo looks like he just ran a marathon.

“That’s as good as it’ll get,” Kyungsoo sighs, reaching up to straighten Jongin’s tie. “Can I borrow some cologne? I don’t have time to shower.”

“Isn’t it better to show up smelling like sex than it is to show up smelling like me?”

Kyungsoo thinks for a moment, but ultimately decides that Jongin is probably right. He walks him to the door, and Kyungsoo is pleased to note a slight limp in his gait.

“Thank you, Jongin,” he says as Jongin turns the lock, leaning up and pressing one last kiss to the elder’s lips. “I’ll see you at the show, right?”

“I wouldn’t miss it for the world,” Jongin replies before opening the door. “And thank you, Kyungsoo.”

-

“Oh thank god; he’s here,” Luhan exhales as Kyungsoo enters the auditorium at 3:57, relaxing visibly as he reviews the papers on his clipboard for the thousandth time this week. “Alright, get onstage, Soo; I want to check our harmonies in Hurt one more time before we start dress rehearsal.”

“Yes sir,” Kyungsoo chimes, bouncing up the steps to the stage and smiling at Minseok and Yixing before taking his place in the front with Baekhyun and Jongdae.

“I see you and professor Kim had a nice session,” Baekhyun whispers with an impish grin, eyeing Kyungsoo’s neck with barely-concealed amusement. Kyungsoo’s heart drops into his shoes.

“…he left marks, didn’t he…”

“What?!” Jongdae gasps, peering around Baekhyun to see what was going on and dramatically falling backwards into an unsuspecting Junmyeon beside him when he sees the hickies. “Fuck, I knew it! I knew it, I knew it, I _knew_ it!”

“Chen, what’s wrong?” Luhan asks. Jongdae might be a loudmouth, but to his credit, he doesn’t say anything incriminating in front of the others.

“Fucking stop rehearsal! I have to talk to Kyungsoo _now!”_

A few people start asking questions at the same time, but Baekhyun’s voice cuts them off.

“How long?”

The question is vague enough that the others won’t catch on, but Kyungsoo knows what he means.

“Two months maybe…?”

“Two _months?!”_ Jongdae shrieks, clinging to a bewildered Junmyeon’s arm as if he can’t stand on his own. “Two months and you didn’t confide in your best _friend?!”_

“Hey, I’m his best friend!” Baekhyun argues childishly, and Kyungsoo can’t help but laugh. As obnoxious as Baekhyun and Jongdae may be, he knows they won’t breathe a word of this to anyone.

They’re too afraid of what he’d do to them if they did.

“Oh Kyungsoo-yah, I’m so proud of you,” Jongdae fake-sobs, enveloping the younger in a tight hug, only to tear away upon smelling the lingering scent of sex on his skin. “No fucking way! I thought you just- oh my god, no fucking _way!”_

It’s pretty funny how stressed Luhan looks as he tries to get the group to focus on the rehearsal at hand, so Kyungsoo doesn’t deflect Jongdae’s incessant questioning. “You’re pretty interested in Kyungsoo’s gay sex life for a straight guy,” Baekhyun comments at one point, earning a slap from Jongdae and laughter from the rest of the onlookers.

-

“Three more months,” Kyungsoo tells his roommate on their way back to the dorms after practice. “Keep it a secret until graduation, and then you can tell whoever you want.”

“It’s that serious?” Baekhyun asks with a dazzling smile that reminds Kyungsoo of a proud mother listening to her son tell her about his boyfriend. “You’re gonna keep seeing him after graduation?”

Kyungsoo smiles to himself, but doesn’t answer right away. There’s a lot he still needs to discuss with Jongin regarding their feelings for each other, but if he has to give Baekhyun an answer now…

“…I feel good about it. We talk a lot more often than we fuck, and he’s actually really adorable in real life.” Kyungsoo glances between the faint orange glow of the Western sky and the twinkling stars of the East as they walk and talk. “And you know I like older guys so… I don’t know. I really think we might have something.”

“Oh god, I’m gonna throw up,” Baekhyun teases, earning a jab in the ribs by Kyungsoo’s elbow. He’s learned in his four years of knowing Baekhyun that sarcasm is the older boy’s way of expressing love, however, and doesn’t object when his best friend slings an arm around his shoulders.

“My baby Kyungsoo’s falling in love,” Baekhyun sings to the night sky, his sharp, clear voice spiraling upwards through the crisp February air.

Kyungsoo doesn’t disagree.


	3. Chapter 3

"What does this one say?" Jongin asks, ghosting his fingertips over a small cursive tattoo on Kyungsoo's collarbone. It's almost midnight, but the spring air is still warm and comfortable as it filters through the open window of Kyungsoo's dorm room. Jongin is curled into Kyungsoo's side like he belongs there, both of them clad in their underwear as Jongin studies the younger's ink like it's the most fascinating thing in the world. 

" _C'est_ _la_ _vie_ ," Kyungsoo tells him. "French for _it's_ _life_." 

"Please tell me you don't speak French; you're already too hot."

Kyungsoo can't help but giggle at that. "Oui, je peux parler un peu de français."

"I don't know what you just said, but it kinda makes me want to wreck you."

"Easy tiger," Kyungsoo laughs, pulling Jongin closer and kissing his forehead. "My ass can only take so much in one night.”

"Amateur," Jongin teases, tilting his head up and catching Kyungsoo's lips. 

"I'd argue, but I was taught to respect my elders," Kyungsoo playfully shoots back, earning himself an insincere slap on the chest. 

Jongin settles back down, nuzzling his face into Kyungsoo's skin and letting his eyes close. "I wish I could sleep here."

"I wish you could too," Kyungsoo says honestly, relishing the warmth of the body next to him. "But in a few more weeks I get to share the bed with you every single night."

"I still haven't cleaned out a closet for you," Jongin thinks aloud, tracing his fingers over the brushed calligraphy tattoo that decorates the right side of Kyungsoo's chest. 

"That's alright, I can live out of a suitcase," Kyungsoo smiles at the professor's pout. "As long as it's with you."

"God, you're so corny," Jongin groans, reluctantly pushing himself into a sitting position and running a hand through his unruly sex hair. "Remind me why I agreed to date you?"

“Cause I'm adorable," Kyungsoo beams up at him. Jongin grumbles because he can't deny it. 

The lock on the door rattles then, and Jongin barely manages to get his pants on before Baekhyun saunters through the doorway.

"Soo, you're never going to believe— oh, hey man," he smiles knowingly at the professor as he hangs up his coat. "Shit, what do I call you? Feels weird calling you Mr. Kim when your shirt's on the floor of my bedroom."

"Yeah," Jongin agrees, blushing slightly despite having had too many conversations with his boyfriend's best friend to feel uncomfortable. "Jongin's alright in private."

"This feels like a sitcom or something," Kyungsoo laughs behind him, getting up to fetch a hairbrush from the bathroom while Jongin feels around on the nightstand for his glasses. "Baekhyun's the gay best friend slash comic relief."

"The ‘gay best friend’ trope doesn't work when everyone involved is gay," the elder student points out, dropping his bag beside his desk and walking over to collapse onto his bed. "Jongdae could be the straight best friend, though."

"Oh please; everyone knows that Jongdae's bi except Jongdae," Kyungsoo rolls his eyes as he goes to fix his boyfriend's hair. "Every time he calls Minseok _bro_ I lose a day off my life."

Jongin laughs at that, sitting on the bed so Kyungsoo can reach the top of his head. “He’ll figure it out eventually,” he says as the younger combs his hair back into place. “I thought I was straight until I was, like, twenty-four.”

“No way,” Baekhyun gasps, sitting upright in his bed. “Dude, what the hell took you so long?”

“Baekhyun!” Kyungsoo admonishes, kicking a bare foot back in his roommate’s direction. “Don’t talk to your professor like that!”

“Shut up Bitchsoo; he’s basically my brother-in-law at this point,” Baekhyun deflects Kyungsoo’s foot with his pillow. “Hyung, what took you so long?”

“My college girlfriend cheated on me, so I hooked up with her brother,” Jongin tells him as he shrugs his shirt back onto his shoulders. “Never even thought about guys that way before that.”

“He’s a stubborn one,” Kyungsoo smiles down at him, leaning down to press a soft kiss to his lips and ignoring the retching sounds Baekhyun makes behind him. “Baby, do you really have to go?”

“Yeah,” Jongin sighs as he buttons his shirt. “It’s late and I have to work in the morning. If I stayed, I’d get caught leaving tomorrow.”

Kyungsoo pouts, but he understands. He helps Jongin back into his jacket and pulls the hood up for him before leaning up for one last kiss.

“Text me?”

“Always,” Jongin smiles back, smoothing Kyungsoo’s hair before replacing his phone in his pocket and opening the door. “Baekhyun, you better have that problem set done by class tomorrow. It’s the last one before we start reviewing for finals.”

“Oh my god, it’s like I can’t even escape it anymore,” Baekhyun moans, rolling over in his bed. “Kyungsoo, tell him he’s not allowed to bring calculus in here!”

“It’s part of the package with him, Baek,” the youngest replies, peeking out into the hall before nodding to Jongin that it’s clear.

“Hey.”

“Hm?”

Jongin’s lips connect with his one more time before he steps into the hall. “I love you, Soo.”

Kyungsoo’s heart thumps in his chest at the words despite this being his umpteenth time hearing them.

“I love you too, Jongin.”

Jongin smiles brilliantly at him before turning and retreating down the hall. Kyungsoo watches until he rounds the corner and disappears from sight.

There are three weeks until graduation.

Three weeks until Kyungsoo will be moving into Jongin’s spacious studio apartment in the city to pursue his singing career. He, Jongdae, and Baekhyun, who is a brilliant pianist, are booking gigs together as a trio for the time being, and Jongin (their biggest fan) is more than willing to help support Kyungsoo financially as he gets off the ground. Enjoying close proximity his gorgeous boyfriend of six months isn’t a downside to giving up his bachelor pad, either.

They’ve gotten better about sneaking around. Jongin drives them out of town for dates on the weekends where there are few university students around, and the more time that they spend together, the more Kyungsoo learns that Jongin is really just a child at heart. He learns how much the elder cares for his sister and niece, learns that his true passion is dance, but that he wasn’t successful in making a career out of it. Kyungsoo croons a jazz ballad one night while Jongin follows the melody, and the way his body moves under the glow of the moonlight takes Kyungsoo’s breath away.

It’s natural with Jongin— more natural than he ever felt with any of his exes. Trying to toss grapes into his boyfriend’s open mouth and laughing when they bounce off his nose instead feels like something they’ve been doing for years. They behave like magnets whenever they're in the same room, but if Kyungsoo’s calculus classmates have noticed anything, no one’s breathed a word. It makes Kyungsoo’s stomach hurt to think that he almost signed up to take Statistics last fall.

“God, you’re a lovesick fool,” Baekhyun shakes his head at him, kicking his jeans off now that their company is gone. “Come change your damn sheets and go to bed, heart-eyes.”

“Nah, I think I’m gonna sleep in them just to gross you out,” Kyungsoo yawns as he crawls back into bed. Baekhyun makes a sound vocalizing his disgust, which in turn brings a smile to the younger’s lips. His pillow still smells like Jongin’s shampoo.

“Whatever. Jerk off in the bathroom this time if you have nasty dreams, would you? I really don’t want another eyeful of your dick when I wake up, thanks.”

That’s Baekhyun for good night, sweet dreams, Kyungsoo knows. “I love you too,” he chuckles, turning onto his side and plugging his phone into the charger. There’s a few twitter notifications and a text from Jongin on his lock screen:

 _Sweet_ _dreams_ , _love_ _bug_.  <3

It’s after twelve, and the countdown on his home screen is one day closer to his graduation date.

One day closer to the first day of the rest of his and Jongin’s lives.

He can’t wait.

**Notes for the Chapter:**

> Thank you for reading! Feedback is appreciated! <3


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